First is grammar, try to improve especially in this paragraph, I'll add some stuff to make it look tidier and nice, let's go.

Any subject approaching within 100 meters from SCP-2630 -may- (may, the reason may might work better than will implies no clear line and makes it more perhaps, mysterious) start feeling weak and unconcansious[I think you mean unconcious].

Subject can remain in this state temporarily (Usually 24-48 Hours) [always have no space behind a coma], or (Rarely) for up to Twenty (20) Years. Subjects also start feeling paranoid for a very long time, and begin to desire to get back to SCP-2630. Any subjects labeled under this state is[are works better here] to be classified as SCP-2630-2 instances, and stored at Cryogenic Vault-██.

So also, during the log, if it's a mummy there in 4000 years, how could it know modern English?
These are the things I see just from skimming, might be more tho, also try to work on the clinical tone, try to not point things out in definite like using can or will, because SCP researches often have no idea what they deal with,

Although I suggest getting a more unique idea other than another random memetic effect assigned to the sarcophagus, like yes, it makes people try to open the sarcophagus but try to make us scared of the tomb getting opened, maybe by give it a scarier personality if you're looking for a creepy character, the language it uses in the logs is really slang-ish and non-intimidating if I was some clueless Class-D.

Fixed the formatting of the quoting for you. Remember to add a space after the > chevron symbol when quoting, and you don't need to add multiple chevrons for the same paragraph. ~Zyn [Thanks Zyn!]

Cartel, instead of posting multiple comments in succession, please edit your previous post using the "edit" function under the "options" tab to the lower right of every comment. That prevents spam buildup, and it's in the rules.

Furthermore, some of this feedback is misleading or too vague to be helpful. When you mention that grammar needs work, you should try to give at least one example of the kind of error that is present, and how it should be fixed. The same applies to clinical tone—especially with newer writers who may not be familiar writing with professional tone, just telling them "work on the clinical tone" doesn't help them at all.

Additionally, what is "a more unique idea"? How would someone who doesn't know what your thought process is be able to guess what you're getting at?

And finally, not everything is sentient, and sentience in itself can be arguably perceived as a spectrum (example, Sentience quotient). It might help next time to define sentience and the difference between it and sapience. (OP, from Wikipedia, sentience is "capacity to feel, perceive, or experience subjectively", while sapience is "the ability to think and act using knowledge, experience, understanding, common sense, and insight".)

For the record, generally the number (#) numeration is generally used for extreme precision measurements that can be fatal if misinterpreted, like drug prescriptions. You don't need to do that here for things as easy to count as "20 years".